Effect of Hepatitis B virus infection during pregnancy on the risk of postpartum hemorrhage: a systematic review and meta-analysis.

Aim: Hepatitis B virus (HBV) infection during pregnancy is one of the most common comorbidities, which may increase the risk of adverse obstetric and perinatal outcomes. However, the association between maternal HBV infection and postpartum hemorrhage (PPH) remains uncertain. The aim of this study is to evaluate whether maternal HBV infection will increase the risk of PPH. Methods: Five English and three Chinese databases were searched from inception to 30 June 2024, with the aim to include recently published eligible studies. Cohort and case-control studies that evaluated the association between maternal HBV infection and PPH were included. The Newcastle-Ottawa scale was used to evaluate the risk of bias for the included studies. We pooled crude relative risk (cRR) and adjusted odds ratio (aOR) as effect sizes. Three subgroup analyses and seven sensitivity analyses were performed. Results: A total of 21 cohort studies involving 379,782 participants were included. The pooled results of the unadjusted data revealed that maternal HBV infection was associated with an increased risk of PPH [cRR = 1.18, 95% confidence interval (CI): 1.06-1.31]. Furthermore, the pooled results of adjusted data showed a similar risk of PPH (aOR = 1.50, 95% CI: 1.29-1.73). The effect was similar in three subgroup analyses (i.e., sample size, study region, and prevalence of HBV infection). Sensitivity analyses confirmed that the primary results were robust. Conclusions: Maternal HBV infection is associated with an increased risk of PPH. Further studies are warranted to evaluate the impact of maternal HBeAg serostatus and HBV DNA levels on PPH. Systematic Review Registration: identifier CRD42023442626.